FLORA OF ICELAND elements: Carex rostrata, Bottle Sedge, Tjarnastör

Carex rostrata; the Bottle Sedge is one of the larger sedges on Iceland. It is about 60 cm tall, sometimes even more. The leaves and culms grow from rootstocks. Bottle Sedge fields can be recognized from a distance by the light green, slightly bluish glare.
  - The leaves are longer than the inflorescences. They are dull green to bluish green on top but shiny green below, 3-5mm wide. The stomata are on the top-side of the leaves. The leaf-margins are raised upwards leading to V-shaped leaves. The bracts too are longer then the inflorescence. The culms are only bluntly triangular, mainly smooth but sometimes slightly rough on top. Plants growing in dryer conditions are often darker green.
  - The inflorescence consists of a few (2-3) male spikes on top and a few (2-4) female spikes below. These female spikes are upright more or less pressed to the stem. The top spike is on a long pedicel. All other spikes are on short pedicels, the lowest on a relative longer pedicel. The scales under the flowers are yellow to brown with a green midrib. They are pointed, but the scales of the male flowers are often less pointed. The female flowers have three stigmas. The utricles are more or less globose with a characteristic long beak.
  - It grows often around ponds and lakes, but also in bogs. In the latter the plants usually stay smaller and less bluish, probably caused by more unfavorable nutrients in bogs.
  - It is a member of the Sedge family (Cyperaceae). The Icelandic name of this species is Tjarnastör.